Retaining device



March 25, 1952 H. MESSINGER 2,590,196

RETAINING DEVICE Filed April 25, 1947 3 r 5* J j.

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Lester ATTORNEY Patented Mar. 25, 1952 UNITED STATES PATENT OFFICE 2Claims. (Cl. 13854) This invention relates to tubing or hose of flexiblematerial used for the ventilation of mines, tunnels, the holds of shipsand purposes of a generally analogous character, and more particularlyto means for reinforcing and supporting such flexible tubing whichinherently is not sufiiciently self supporting to alone retain itsexpanded form.

For many years it has been the practice to use flexible, fabricventilating hose or tubing to ventilate remote spaces in mines, tunnels,ships holds and similar places by supplying fresh air under positivepressure to these isolated spaces. Such flexible tubing is usuallyimpregnated or coated with rubber or like material and is generally madein sections varying in length so as to be conveniently connectedtogether to form a continuous air passage to the desired'point.

Mine ventilating tubing of the character to which my invention isapplicable is disclosed in a number of United States patents includingNo. 1,671,706, May 29, 1928, No. 1,779,258, October 21, 1930, and No.1,863,624, June 21, 1932.

Toprovide internal support for such thinwalled, flexible, ventilatingtubing atturns in its course it has been proposed in U. S. Patent No.2,345,636 to provide short, collapsible, wire helices which arepositioned inside the sections of tubing. When not in use as supportingmembers the wire helices are withdrawn from the tubing and collapsed bycompressing the successive coils together and retaining the coilsclosely adjacent to each other by means of clamps which are adapted tohold the circumferential portions of the two terminal coils of the helixto- 'gether and retain all intermediate coils in axially compressedposition between the terminal coils, to facilitate handling and storageuntil further need for them arises.

A principal object of this invention is to provide a greatly improvedbut inexpensive, reliable retaining device for holding the coils of thesupporting wire helices in collapsed condition.

A further object is to provide such a retaining means positioned withinthe helix in such a manner as to be out of contact with the walls of thetubing supported by the helix;

' Another object is to 'provide' such -a retaining means integral withthe wire coils themselves,

thereby reducing the weight, increasing the strength, and simplifyingfabrication.

- Other objects will become apparent from the following description inwhich:

Figure l is a side longitudinal sectional view of a-length of flexible.ventilati-hgtubing supported by a wire helix constructed in accordancewith my invention, the right hand end coil of the helix being shown infull for purposes of clarity while the remaining coils of Figure 1 areshown in section.

Figure 2 is a similar section of an axially compressed helix embodyingmy invention wherein the righthand end coil is shown in full while theremaining coils of Figure 2 are shown in section.

Figure 3 is a detail View of the retaining device of this invention inengaged position, the coils retained thereby being omitted for purposesof clarity.

Figure 4 is a side elevation of one type of clamp which can be used inconnection with my invention.

Figure 5 is an end view of the clamp shown in Figure 4.

Figure 6 is a broken sectional plan view of a partial length of tubing,bent at an extreme angle topermit the negotiation of a sharp turn,supported by an extended helical member constructed in accordance withmy invention, the maintenance of the bend being faciliated by theutilization of a clamp of the design of Figures 4 and 5.

Referring more specifically to the figures of the drawing, Figure 1shows a single, wire helix embodying my invention in supporting positionwithin a section of flexible ventilating tubing. These helices arefabricated from spring wire of appropriate thickness and normally assumethe extended position shown unless forcibly retained by other means. Thesupporting helices are formed in slightly smaller diameter than theinside diameter of the tubing to be reinforced thereby so that they maybe easily moved within the tubing as conditions of use may require.Preferably the supporting helices are fabricated in varying lengthswhich generally comprise fourteen to sixteen coils.

When not required as supporting members the helices are ordinarilywithdrawn from the lengths of tubing, since, in the compressed formshown in Figure 2, they would offer considerable obstruction to thepassage of air through the tube if they should rotate so that thecompressed coils lay across the plane of air flow. To facilitate storagethe withdrawnhelices are compressed to the 'form shown in Figure 2 andlaid aside until they are again required.

In Figure 1, the terminal ends of the helical, wire supporting memberare shown as formed into retaining elements which are designated I and2, respectively. In the formation of these elements care is taken toinsure that the wire length designated 3, shown only for the righthandelement, follows the true helical course which all intervening coilstake so that, when the helix is compressed to the form shown in Figure2, all coils will contact their next adjacent coils around their entirecircumferences, and the resulting bundle will assume a tight cylindricalform in which no single coil will lie outside or inside the limits ofthe cylinder thereby defined, but all will be neatly superimposed one onthe other.

Retaining elements i and 2 are hooklike in form and are identical inshape, but element 2 is so disposed that the plane parallel to its hookportion lies at an angle of approximately ninety degrees to the planeparallel to the hook portion of element 1. The open portions of thehooks of I and 2 face outwardly, in opposite directions and away fromthe intervening coils.

The shank portions l of the hooks i and 2 are inclined at slightlyopposite acute angles to the longitudinal axis of the helix when it isextended, but lie along the longitudinal axis of the cylinder formedwhen the helix is compressed. The disposition of the shank portions arelative to the longitudinal axes in the extended and compressedconditions is an important feature of the construction, since .ichfacribation insures the balanced application of stresses over thecomplete circumferences of the coils and thereby insures that all coilswill naturally superimpose one on the other in a condition of maximumstability when the helix is compressed to the position of Figure 2.

As shown in Figure 3, which depicts the reretaining elements and 2 inconnected relationship, the hook portions are formed at the ends of thewire and constitute a continuation of the straight shank portions 4which, in turn, are bent at angles of approximately ninety degrees tothe straight lengths of wire 5 which continue on to form the helix. Theshank portions 4 are of approximately equal length and about one half ofthe length of the compressed coil of Figure 2 so that, when elements iand 2 are engaged, the point of engagement will approxi-- matelycoincide with the geometrical center of the cylinder formed by the axialcompression. The straight lengths of wire 5 are each approximately equalto the radius of the helix.

The hook ends of both elements are bent back parallel to the shankportions 4 at an angle of approximately one hundred and eighty degrees,and the free ends extend a distance of less than the half the length ofthe shank portions. The inside curves of the hook portions are madesomwhat greater than the diameter of the wire to facilitate easyengagement and disengagement without pinching of the wire in the hookcurves. It will be understood that the wire of the. helix is ofsufficient inherent strength and stiffness as to maintain the shapes andangles to which the end portions are bent, both under the strain ofaxial tension and under the other strains encountered in normal use. g

It is possible to remove the supporting helices from the tubing sectionsin the'extended conditions of Figure l, but it is usually morepreferable to compress them to the compact form of Figure 2 prior toremoval from the tubing. The supporting helices are easily compressedand their retaining elements engaged, one with the other, bymanipulation through the walls of the tubing-when the air flow ismomentarily. discontinued, since the tubing walls are easily flexed inany desired direction under these condtions. An attendant is therebyenabled to ascertain the location of the end members of each helix bytouch against the tubing wall, and, when both ends are under control ofthe operator, the helix may be compressed by forcing the outside coilstogether and then engaging elements I and 2, whereupon the helix will bemaintained in compact, shortened form until elements I and 2 arepositively disengaged at the will of the attendant.

Figure 6 shows a length of tubing bent at a sharp angle of about ninetydegrees and supported by a wire helix fabricated in accordance with myinvention. To facilitate the maintenance of such a bend it is sometimesdesirable to employ a clamp 9 to retain and support the central coils,which are subjected to the highest stresses due to the bending. Onforming the bend there will also be some slackness in the tubing wall atthe inside of the bend, and it is desirable to gather this slackmaterial at a central point in such a manner that it will he outside thewire coils and not constitute a hindrance to the air passage within thetube. This dual function is accomplished by the clamp 9 which is shownin detail in Figures 4 and 5.

The clamp 9 comprises three freely separable elements, the two jaws orhook-like straps 5 and the square cross section, joining bar Thisconstruction permits ready disassembly of the three component parts bymerely sliding the hook straps 6 from the central bar 1, whereupon thestraps can be hung from hooks on a workmans belt while a number of thebars may be gathered into a compact bundle, making it easy to trans portthe clamps through the narrow confines within which ventilating tubingis usually installed. When a clamp 9 is needed for the purposesdescribed the two hook straps 6 are slid over the square bar 1 inopposed relationship, and the central coils and slack tubing aregathered in the space between the straps, after which the two straps arepushed firmly together. Because of the elasticity of the coils, acounter force is exerted at an acute angle to the straps which tends torotate them about an axis perpendicular to bar I. Bar 1 resists suchforce moments, and the straps 6 thereupon bind on bar I, forming astable clamp which may be easily disassembled by an attendant wheneverdesired.

Clamps 9 are not intended for holding the ventilating tubing to anysurrounding supporting surfaces but only to retain the central coils andthe fabric slackness occurring at tubing bends. It is customary tosupport the ventilating tubing by hanging it from wires strung alongwalls and ceilings, the wires being threaded through, or otherwiseengaged with, fabric or metal tab pieces 8 carrying central eyelets,which tab pieces are sewn, riveted or otherwise joined to the tubingwalls at appropriate intervals and which are in no manner associatedwith the supporting helices.

The retaining devices made in accordance with my invention are simpleand economical to manufacture, are of high strength, and possess theadditional advantage of not chafing or puncturing the tubing wallsbecause they do not bear against them.

As many apparently widely different embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that I do not limit myself to 5 the specific embodimentsthereof, except as defined in the appended claims.

I claim: 1. An internal support for flexible gas-conducting tubingconsisting of an extended wire helix, and means within the periphery ofthe a helix for holding said helix in collapsed or compressed condition,comprising mutually engageable means integral with the ends forminghooks made from the ends of said wire helix and reposing wholly withinthe helix.

2. The invention of claim 1 in which the hook members are made of thesame tension material as the wire helix.

LESTER H. MESSINGER.

6 REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 439,210 Thome Oct. 28, 18901,711,300 Ziegler Apr. 30, 1929 2,345,636 Stickler Apr. 4, 1944 FOREIGNPATENTS Number Country Date 10,567 Great Britain of 1915

